Explore the evidence
10 of 88 decisions · clear everything
Later bells buy adolescents 40+ measured minutes of sleep — the best-identified positive effect in the archive; the achievement payoff is real but far smaller.
strong supportconf: mediumgc: lowDo later school start times increase adolescent sleep, and does that raise achievement? · health · ages 11–18 · input
Mixing problem types helps where confusion is the enemy — discriminating similar categories, mixed math practice — and is useless or worse for facts and prose.
moderate supportconf: mediumgc: lowInterleaving (mixing problem types vs blocking) · practice · ages 10–18 · method
Diagnose what a child already knows: teachers cut 40–50% of curriculum for high-ability children and achievement ROSE. The payoff is skipping, not monitoring.
moderate supportconf: mediumgc: mediumPlacement and mastery diagnosis — deciding what to teach next from evidence of current skill · assessment · ages 5–18 · structure
Novices learn faster studying solutions than solving problems — then the effect reverses with expertise. Use worked examples early; fade them.
moderate supportconf: mediumgc: lowWorked examples (studying solutions vs solving problems) · instruction-style · ages 10–18 · method
Correcting a real deficiency moves cognition (iron in anaemic children: 0.79 SD); supplementing already-fed children moves nothing (35 RCTs, 19,343 children).
mixedconf: mediumgc: lowBreakfast, school meals, and micronutrients — what feeding children actually buys · health · ages 4–18 · input
A missed day costs little (~0.005 SD); interventions reliably buy days back cheaply, but nobody has shown the recovered days move achievement.
mixedconf: mediumgc: mediumChronic absenteeism — does raising attendance raise achievement? · time · ages 4–18 · input
Near-zero in primary and almost entirely correlational in secondary. The causal base is three small trials; what the homework IS beats how much of it there is.
mixedconf: mediumgc: mediumHomework — effects by age and by dosage · homework · ages 5–18 · structure
Classroom order is causally worth a great deal — one disruptive peer costs classmates 3% of adult earnings — yet no branded behaviour programme reliably delivers it and exclusion makes things worse.
mixedconf: mediumgc: lowHow should a school run its classrooms and its discipline system? · behavior · ages 4–18 · structure
What parents are asked to DO is the whole effect: tutoring a skill d≈1.15, listening to reading 0.51, reading aloud ~0.18 — same parent, same child. All deflate under better designs.
mixedconf: mediumgc: mediumThe parent as instructor — what survives when the person teaching is the person who raised the child · homeschool · ages 4–18 · method
Trust the composite; distrust the breakdown. Subtest strengths-and-weaknesses replicate at chance on retest, and most of what people read off a score report is noise.
mixedconf: mediumgc: lowWhat a standardized achievement score does and does not license · assessment · ages 5–18 · structure
The URL is the state — any view you build here is a permalink you can hand to someone mid-argument.